The invention relates to a picture display device having a vacuum envelope for displaying pictures composed of pixels on a luminescent screen, and particularly relates to a thin picture display device (i.e. a picture display device having a small "front-to-back dimension") which is clearly distinguished from state-of-the-art display devices.
Typical state-of-the-art approximations to thin-type picture display devices are devices having a transparent face plate and a rear plate which are interconnected by means of partitions and in which the inner side of the face plate is provided with a phosphor pattern, one side of which is provided with an electrically conducting coating (the combination also being referred to as luminescent screen). If (video information-controlled) electrons impinge upon the luminescent screen, a visual image is formed which is visible via the front side of the face plate. The face plate may be flat or, if desired, curved (for example, spherical or cylindrical).
A specific category of picture display devices of the thin type uses single or multiple electron beams which initially extend substantially parallel to the plane of the display screen and are ultimately bent towards the display screen so as to address the desired areas of the luminescent screen either directly or by means of, for example, a selection grid structure. (The expression electron beam is understood to mean that the paths of the electrons in the beam are substantially parallel, or extend only at a small angle to one another and that there is a main direction in which the electrons move). The above-mentioned devices operating with controlled electron beams require, inter alia, complicated electron-optical constructions.
Moreover, picture display devices of the single beam type generally require a complicated (channel plate) electron multiplier of the matrix type, certainly if they have slightly larger screen formats.